Make failing test not hang

[ellert]

The tests/test_radio_dish test implements is_multicast_available() to verify that multicast is working on the system before running tests that relies on this, or skipping those test otherwise.

In some circumstances this check itself hangs due to the recvfrom() call being blocking waiting for data. The test is eventually killed with a SIGALARM signal.

./config/test-driver: line 112: 1227308 Alarm clock "$@" >> "$log_file" 2>&1
FAIL: tests/test_radio_dish

FAIL tests/test_radio_dish (exit status: 142)

$ tests/test_radio_dish
tests/test_radio_dish.cpp:511:test_leave_unjoined_fails:PASS
tests/test_radio_dish.cpp:512:test_join_too_long_fails:PASS
tests/test_radio_dish.cpp:513:test_long_group:PASS
tests/test_radio_dish.cpp:514:test_join_twice_fails:PASS
tests/test_radio_dish.cpp:515:test_radio_bind_fails_ipv4:PASS
tests/test_radio_dish.cpp:516:test_radio_bind_fails_ipv6:PASS
tests/test_radio_dish.cpp:517:test_dish_connect_fails_ipv4:PASS
tests/test_radio_dish.cpp:518:test_dish_connect_fails_ipv6:PASS
tests/test_radio_dish.cpp:519:test_radio_dish_tcp_poll_ipv4:PASS
tests/test_radio_dish.cpp:520:test_radio_dish_tcp_poll_ipv6:PASS
tests/test_radio_dish.cpp:521:test_radio_dish_udp_ipv4:PASS
tests/test_radio_dish.cpp:522:test_radio_dish_udp_ipv6:PASS
Alarm clock

With this commit, making the recvfrom() call non-blocking. The test does noy hang, and the non-available multicast is detected and the tests needing it are skipped:

PASS: tests/test_radio_dish

$ tests/test_radio_dish
tests/test_radio_dish.cpp:510:test_leave_unjoined_fails:PASS
tests/test_radio_dish.cpp:511:test_join_too_long_fails:PASS
tests/test_radio_dish.cpp:512:test_long_group:PASS
tests/test_radio_dish.cpp:513:test_join_twice_fails:PASS
tests/test_radio_dish.cpp:514:test_radio_bind_fails_ipv4:PASS
tests/test_radio_dish.cpp:515:test_radio_bind_fails_ipv6:PASS
tests/test_radio_dish.cpp:516:test_dish_connect_fails_ipv4:PASS
tests/test_radio_dish.cpp:517:test_dish_connect_fails_ipv6:PASS
tests/test_radio_dish.cpp:518:test_radio_dish_tcp_poll_ipv4:PASS
tests/test_radio_dish.cpp:519:test_radio_dish_tcp_poll_ipv6:PASS
tests/test_radio_dish.cpp:520:test_radio_dish_udp_ipv4:PASS
tests/test_radio_dish.cpp:521:test_radio_dish_udp_ipv6:PASS
tests/test_radio_dish.cpp:431:test_radio_dish_mcast_ipv4:IGNORE: No multicast available
tests/test_radio_dish.cpp:431:test_radio_dish_no_loop_ipv4:IGNORE: No multicast available
tests/test_radio_dish.cpp:431:test_radio_dish_mcast_ipv6:IGNORE: No multicast available
tests/test_radio_dish.cpp:431:test_radio_dish_no_loop_ipv6:IGNORE: No multicast available

---

16 Tests 0 Failures 4 Ignored
OK

[bluca]

D:\a\libzmq\libzmq\libzmq\tests\test_radio_dish.cpp(410,54): error C2065: 'MSG_DONTWAIT': undeclared identifier [D:\a\libzmq\libzmq\build_libzmq\tests\test_radio_dish.vcxproj]

[ellert]

D:\a\libzmq\libzmq\libzmq\tests\test_radio_dish.cpp(410,54): error C2065: 'MSG_DONTWAIT': undeclared identifier [D:\a\libzmq\libzmq\build_libzmq\tests\test_radio_dish.vcxproj]

Better?

[bluca]

Please push the release tags from the upstream repo to your github fork (git push --follow-tags), that way the OBS SCM/CI workflows can also run and test the changes in more environments